IDDF2021-ABS-0069 Ecology and network analyses for the fecal microbiome in ulcerative colitis (UC)

Abstract

<h3>Background</h3> The incidence of IBD in China (about 3. 44/100,000) ranks first among Asian countries. The most difficult thing is that its pathogenesis is still unclear, especially the role of the gut bacteria in host intestinal immune development and defense. This study aimed to analyze the changes in the fecal microbiome associated with UC from the perspectives of medical ecology and complex network analysis. <h3>Methods</h3> We analyzed 56 fecal microbiome from 28 Chinese UC patients and their mates, consecutively enrolled at the First Affiliated Hospital of Kunming Medical University between 2018 to 2019. The effects of UC on the species diversity, species composition and interspecies interaction of fecal microbiome were analyzed and compared at three levels: the community as a whole, the main flora, and the core/peripheral species. <h3>Results</h3> After amplicon sequencing and bioinformatics analyzing, in total, 1130 OTUs were identified, in which there were 632 and 666 OTUs in the fecal microbiome of the healthy and UC groups, respectively. In fecal microbiome, the diversity (at diversity order q=0) of Bacteroidetes in fecal microbiome was significantly higher in the healthy group than UC group (table 1). And there is a significant difference between their microbial compositions (table 2). For the fecal mucosa, the P/N ratio of the healthy group was similar to that of the UC group (figure 1~2). With both A1 and A2 algorithms, the observed number of shared core/periphery species was significantly smaller than that expected by chance (table 4). <h3>Conclusions</h3> In our study, we innovatively proposed that Hill number for the gut microbe diversity. Then in order to detect whether there was a statistical difference in core (or periphery) species composition between the healthy and UC groups or between the fecal and mucosa microbiome, we adopted a shared core/periphery network (CPN) analysis. Understanding the microbial characteristics and interactions of patients with ulcerative colitis may provide a mechanistic explanation for ulcerative colitis susceptibility and optimize treatment and prevention measures based on individual differences. So this can be a key foundation for precision medicine.